Features

• All Fiber Technology
• Bi-Directional
• Low Loss
• Wide Wavelength Range
• Damage Threshold is Not Limited by Polarization Region

Applications

• Polarization Measurement and Control
• Coherent Transmission
• High Power Lasers (e.g., Fiber Lasers)
• Optical Sensors
• Test and Measurement Instrumentation
• Navigation Instrumentation

Chiral Photonics’ all-glass, intrafiber polarizers provide a high extinction ratio (PER) over a broad spectral range at a price well below other in-line polarizers. Based on Chiral Photonics’ innovative technology, these intrafiber polarizers feature small size (42 mm) and a high extinction ratio (>30 dB).

The Chiral polarizers are available at four wavelengths (980, 1064, 1310, and 1550 nm) with polarization maintaining pigtails and at 1550 nm with single mode pigtails. For PM pigtailed devices with FC connectors, the key of the FC/PC connector is aligned with the slow axis of the PM fiber.

The in-fiber linear polarizers are manufactured by Chiral Photonics using their proprietary chiral technology developed by Drs. Azriel Genack and Victor Kopp, distinguished physicists at City University of New York. Unlike conventional single-mode optical fibers that guide light using a concentric circular core and cladding, the chiral fibers are manufactured by heating and twisting the fiber. Varying the geometry of the core (square, oval, off center, etc.) and the period produces a chiral fiber with different characteristics.

Using a fiber with a square core produces a double-helical core. This double-helical structure causes light with the same handedness as the fiber to be scattered out of the core, while light with opposite handedness continues within the core. The twist length, or period, determines the performance of the device.

A chiral structure with a relatively loose twist (a period of ~100 μm) scatters light into the cladding, where it is coupled into the cladding modes. These types of structures are beneficial to a multitude of sensor applications, such as pressure, temperature and torque sensors.

In gratings with a reduced twist period (~10 µm), the photons are scattered out of the core at larger angles and no longer couple into the cladding. These moderately twisted structures are the basis for the in-line polarizers we are offering here.

As the period of the twist is further reduced to ~1 μm, the photons with the handedness of the chiral core are back-reflected within the fiber’s core. The wavelength and polarization of the reflected photons are controlled by the pitch and handedness of the twist. These tightly twisted chiral fibers are a promising replacement for fiber Bragg gratings (FBGs), as well as the basis for highly efficient fiber lasers.

The figure below shows the various structures of the chiral fibers based on the twist period. There is also an instructional animation produced by National Science Foundation that demonstrates how chiral structures work.

Image copied from Chiral Photonics non-confidential Power Point presentation.

Light with the same handiness of the chiral structure is show with red arrows, while light with the opposite handiness is represented by blue arrows.